package ar.com.android.restoapp.utils;

import java.security.NoSuchAlgorithmException;

import javax.crypto.Cipher;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

public class MCrypt {

	private String iv = "#EDC4rfvf2d2r3c4";//Dummy iv (CHANGE IT!)
	private IvParameterSpec ivspec;
	private SecretKeySpec keyspec;
	private Cipher cipher;
	
	private String SecretKey = "f2d2r3c4#EDC4rfv";//Dummy secretKey (CHANGE IT!)
	
	public MCrypt()
	{
		ivspec = new IvParameterSpec(iv.getBytes());

		keyspec = new SecretKeySpec(SecretKey.getBytes(), "AES");
		
		try {
			cipher = Cipher.getInstance("AES/CBC/NoPadding");
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		} catch (NoSuchPaddingException e) {
			e.printStackTrace();
		}
	}
	
	public byte[] encrypt(String text) throws Exception
	{
		if(text == null || text.length() == 0)
			throw new Exception("Empty string");
		
		byte[] encrypted = null;

		try {
			cipher.init(Cipher.ENCRYPT_MODE, keyspec, ivspec);

			encrypted = cipher.doFinal(padString(text).getBytes());
		} catch (Exception e)
		{			
			throw new Exception("[encrypt] " + e.getMessage());
		}
		
		return encrypted;
	}
	
	public byte[] decrypt(String code) throws Exception
	{
		if(code == null || code.length() == 0)
			throw new Exception("Empty string");
		
		byte[] decrypted = null;

		try {
			cipher.init(Cipher.DECRYPT_MODE, keyspec, ivspec);
			
			decrypted = cipher.doFinal(hexToBytes(code));
		} catch (Exception e)
		{
			throw new Exception("[decrypt] " + e.getMessage());
		}
		return decrypted;
	}
	

	
	public static String bytesToHex(byte[] data)
	{
		if (data==null)
			return null;
		
		int len = data.length;
		String str = "";
		for (int i=0; i<len; i++) {
			if ((data[i]&0xFF)<16)
				str = str + "0" + java.lang.Integer.toHexString(data[i]&0xFF);
			else
				str = str + java.lang.Integer.toHexString(data[i]&0xFF);
		}
		return str;
	}
	
		
	public static byte[] hexToBytes(String str) {
		if (str==null) 
			return null;
		else if (str.length() < 2) 
			return null;
		else {
			int len = str.length() / 2;
			byte[] buffer = new byte[len];
			for (int i=0; i<len; i++) 
				buffer[i] = (byte) Integer.parseInt(str.substring(i*2,i*2+2),16);
			return buffer;
		}
	}

	private static String padString(String source)
	{
	  char paddingChar = ' ';
	  int size = 16;
	  int x = source.length() % size;
	  int padLength = size - x;

	  for (int i = 0; i < padLength; i++)
		  source += paddingChar;

	  return source;
	}
}